Try:

Try to change testjsp-view.jsp and go to the url again, you will see the change instantly.

Go to this url:

1

http://localhost:8080/staticfile.txt

Try to change staticfile.txt and go to the url again, you will see the change instantly.

Try to change java class, for example, TestController.java. But Spring Boot will not see the change in java file, it will see the change in class file. So, you need to recompile the file. In IntelliJ, you can just shift + F9.